Heavy liquid or suspension



Patented Apr. 6, 1943 HEAVY LIQUID OR SUSPENSION Andrew Pearson, BesselsGreen, Sevenoaks, England, assignor, by mesne assignments, to TheSink'and Float Corporation, New York, N. Y., a corporation of New York INo Drawing. Application May 11, 1940, Serial No.

, 334,641. In Great Britain May 10, 1939 2 Claims. (Cl. 252-450) Thisinvention comprises improvements in or relating to processes .ofspecific gravity separation and to heavy liquids or suspensions such asare used as differentiating media in sink--andv v float or gravityprocesses of separating solid ma terials of different specificgravities.

Suspensions of finely ground solid constitu cuts in aqueous liquids areof advantageous application in the concentration of ores and thecleaning of coal but for various reasons it has been found to bedesirable to'adjust or increase the density of the suspensions, forinstance to control the viscosity and improve the stability or to suitthem to a wider range of use. 7

In the specification belonging to my earlier patent application No.310,411, filed December 21, 1939, I have made the disclosure that susofarsenical ores of nickel and cobaltiarsenides of nickel and cobalt).

The preparation (grinding) of these substances for use may be similar tothat referred to in connection with cement copper in the specificationaforesaid or it may be of any other appropriate nature.

It is preferable to resort to preliminary preparation of the products byquenching them with, or subjecting them to the cooling action of, wateror other aqueous medium as aforesaid. The eco nomical advantages of thisprocedure will be pensions having specific gravities considerablyheavier or greater than those previously obtained can be produced by theuse of metals in a fine state of division, the metals, for example iron,ierro-alloys, metallic copper and copper alloys, therein contemplatedbeing such as to be capable of recovery by magnetic separation or frothflotation.

According to this invention, it has now been established that inaddition to the use of metals,

very favourable results can be obtained by the employment, for thepreparation of the finelydivided solid component of the suspensions, ofmetal mattes or speisses.

In the production of suspensions of the nature described, it is ofimportance to havethe solid constituents in a very, fine stateofdivision and in further accordance with the present invention it hasnow been found that the subjection of appropriate metal products andmetal mattes, or

mediately after discharge from the furnace or after casting into pigs'orthe like), to the 'quenching or cooling action of water or other aqueousmedium is a highly advantageous and economical method of treatment ofthese substances prior to grinding. r

The effect of water and like media is to subject, the heated substancesto thermal shock which renders them crystalline and generally results ina breaking up, thus making themmuch easier to grind to the fine state ofdivision desirable for heavy liquids or suspensions.

As examples of the metal mattes, mention may be made of copper-matte,nickel-matte and copper-nickel matte or mixtures thereof. Ihe speissesare such as are obtained in the smelting readily realised if, forexample, reference is directed to the smelting of sulphide copper ores.A normal smelting operation comprises the treatment of the ores first ina reverberatory furnace from whence matte is tapped into a ladle andtransported to a converter for further treatment. From such an operationproducts ranging from matte to blister are obtained which in the normalcourse of the process may be poured intosand moulds or channels andthere sprayed .with water or be dropped directly into water to granulatethem. Thus, in the normal smelting process a divided product can beobtained and produce the requisite suspension solid.

Similar considerations apply in the case of nickel and other metalmattes or the like. Moreover, other metal products ormetallurgicalfurnace products such as ferro-alloys. speisses and thelike can be brought to a preliminarily broken up or crystalline state byquenching in a similar manner.

In thus providing a material which is easily or more readily ground tothe desired fine state of division for heavy liquids or suspensions, theinvention leads to important economical advantages, and the inventionincludes within its scope material produced in the manner described andsubsequently ground.

As a further modification, the metal products and metal mattes and otherfurnace products referred to may be used in combination with otherproducts and particularly metallic or nonmetallic minerals in a suitablyfine state of division, such, for example, as base metal concentrates,such as copper-, copper-nickel-, lead-,

'lead-zincor zinc-concentrates, or clay, barytes,

by magnetic separation or by froth flotation and the speisses and byfroth flotation or ordinary gravity methods.

The invention also includes within its scope processes of sink-and-fioator gravity concentration comprising the employment,.for the heavy liquidor suspension, of the substances described. It also includes theemployment in gravity sep aration processes of suspensions in aqueousvehicles of mixtures of the finely divided metal products, metal mattes,speisses, and the like.

The suspensions may be used for the separation of ores or of otherdivided solid materials oi diflerent specific gravities. A verydesirable feature of the use of metal mattes or speisses as the solidcomponent of the medium for the separation of ores is that the ore isnot contaminated, as is the case when galena is used as the solidcomponent for the separation of ores other than lead.

In the production of suspensions of the different substances, the lattermay be used in combinations of line or colloidal particles andrelatively coarse particles in the aqueous medium. For instance, themetal products or the mattes or other furnace products might be used asthe coarse fraction and metallic or non-metallic minerals as thecolloidal or fine fraction, or vice versa.

The substances and suspensions referred to are of advantageousapplication in carrying out the invention forming the subject of myapplication Serial No. 233,745 dated October 7, 1938, according to whicha method of concentrating ores and other minerals by the sink-and-floatprocess using stable heavy suspensions is provided, in which thetendency of the viscosity of the suspension to increase during thecourse of the concentration process is kept under control,

by adjusting the relative proportions of fine and coarse particles inthe dispersed phase whilst keeping the specific gravity of thesuspension substantially constant, said adjustment being eflected byremoving a part of that portion of the dispersed phase the particle sizeof which is intermediate between that approaching colloidal size andthat which settles rapidly and replacing same by a suitable amount ofdispersed phase of larger. particle size. In such a method, thesubstances and suspensions of the present invention are able to satisfythe required conditions of the dispersed phase with a high degree ofefficiency and economy.

I claim:

1. A process for the production of a sink-andfloat separating medium,which is substantially stable when in quiescent condition, whichcomprises, comminuting a solid material selected from the groupconsisting of metal mattes and speisses, to form a mass of smallparticles of sizes suitable for use as the dispersed phase in asubstantially stable separating medium, and suspending the same in anaqueous liquid to form a medium of desired specific gravity.

2. A process for the production of a sink-andfloat separating medumwhich is substantially stable when in quiescent condition, whichcomprises, quenching a hot metallurgical furnace product selected fromthe group consisting of metal mattes and speisses by a cold aqueousmedium, comminuting the quenched material to form a mass of smallparticles of sizes suitable for use as the dispersed phase in asubstantially stable separating medium, and suspending the same in anaqueous liquid to form a medium of desired specific gravity.

ANDREW PEARSON.

